Esters of hydroxy-aromatic thioacids



United States Patent 3,338,947 ESTERS 0F HYDROXY-AROMATIC THIOACIDS Gilbert H. Berezin, Newark, Del., and Guy H. Harris,

Concord, Calif., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Feb. 3, 1964, Ser. No. 342,281 4 Claims. (Cl. 260-455) The present invention relates to new and useful esters of aromatic thioacids. More particularly the present invention concerns a novel process for preparing certain esters of hydroxy-aromatic thioacids and to the novel products produced thereby.

This application is a continuation-in-part of our earlier filed application Ser. No. 140,998, filed Sept. 27, 1961, now abandoned.

In accordance with the present invention an aryl ester of S-alkyl thiocarbonic acid is heated in the presence of a Friedel-Crafts catalyst until evolution of HCl ceases. The result of such operation is the rearrangement of the ester to form the hydroxyaryl thioate. The reaction conveniently can be illustrated by the following equation:

o 1s0o.

wherein R represents a primary aliphatic radical having from 1 to 18 carbon atoms or aryl, rt represents an integer from 1 to 2, Ar represents an aromatic nucleus. The preparation of the ester which can be rearranged follows the general equation:

a BDtO The symbols Ar, n and R have the aforesaid significance. The compounds (I) are useful for the control and eradication of undesirable vegetation. Further, some of these compounds have utility as fungicides. The hydroxy compound employed to. prepare the ester in accordance with Equation II can be substantially any aromatic hydroxy compound which has an ortho or para position tree from substituents and which contains no substituent reactive under the condition of reaction other than aromatic hydroxyl, nor nitro, cyano, or other strongly deactivating group. Thus, the aromatic nucleus is derived from a hydroxy aromatic compound of the benzene series or naphthalene series, a diphenol or alkylene bisphenols (hereinafter referred to as phenols), having a least one position ortho or para to the hydroxyl free of substitution. It is to be understood that the aromatic nucleus can be substituted with halogen, alkoxy, alkyl and other substituents not reactive under the conditions of reaction. Some of such compounds useful in accordance with the present invention providing the aromatic nucleus are the phenols, i.e., the cresols, the methoxyphenols, the monoand polyalkylphenols, the phenylphenols, the alkylidene bisphenols, the diphenols, and the resorcinols and the like as well as their alkyl-, alk-oxyand halo-substituted derivatives. Exemplary of the above classes are phenol, 0-, m-, or p-cresol, 3,5-, 3,4-, 2,4-, 2,3- or 4,5-dialkylphenols, diphenol, 0-, por m-alkoxyphenol, p-chlorophenol, 2-chloro-4-methylphenol, naphthol, 2,2'-isopropylidenebisphenol, methylenebisphenol, resorcinol and the like.

The thiochloroformates which can be employed to prepare the esters in accordance with the Equation II are those having the formula wherein R represents a saturated primary aliphatic hydrocarbon radical having from 1 to 18 carbon atoms, aryl,

as well as phenyl, alkylphenyl, halophenyl, alkylhalophenyl thiochloroformates and the like.

The reaction conditions for carrying out the thiol ester formation are:

Temperature: 0 to about C. and preferably about room temperature.

Time: The length of time of reaction is not critical, some of the desired ester being produced in several minutes. However, at room temperature, most esterifications require from several minutes to several hours or even several days when operating at 0 C.

Solvents: When the organic bases are employed as hydrogen chloride acceptors no solvent is usually necessary. However, in some instances an inert solvent facilitates the reaction. When the inorganic bases are employed as hydrogen chloride acceptors it is advantageous to employ them in aqueous solution. Thus water becomes the reaction solvent.

Hydrogen chloride acceptors: Substantially any organic or inorganic base can be employed as a hydrogen chloride acceptor. Preferably, however, the tertiary amines and alkali metal hydroxides are employed because of ready, inexpensive availability, ease of handling and, in the case of the organic tertiary amines, ease of recovery and regeneration. Thus one can employ the tertiary amines such as pyridine, trimethylamine, triethylamine, the alakli metal hydroxides such as sodium hydroxide, potassium hydroxide and the like.

The reaction conditions for carrying out the rearrangement reaction of the present invention are:

Temperature: 0 to about C. Above about 180 C. side reactions occur which reduce the yield of desired product. Heating should be discontinued upon cessation of evolution of HCl.

Time: The length of time of reaction is not critical, some of the desired product being produced even with relatively. short periods of reaction. The reaction usually is carried out until the evolution of HCl ceases. The reaction continues for about 15-30 minutes at the higher end of the temperatures, two to four hours at the intermediate temperatures and for from one to several days when operating at the lower end of the temperature range.

Solvent: Substantially any inert organic solvent can be employed. Thus 'one can employ carbon disnlfide, the halogenated saturated aliphatic hydrocarbons such as tetrachloroethane, the substituted benzenes such as nitrobenzene, the halogenated benzenes, such as, dichlorobenzene, and the like.

Catalyst: Any Friedel-Crafts catalyst can be employed. Representative of such are AlCl SnCl TiCl BF ZnCl ZnBr AlBr SnBr TiBr and the like. The amount of catalyst is not critical. However, best results are obtained when the catalyst is employed in about equimolar proportions.

One manner of preparation of the starting thio-carbonic acid ester is hereinafter set forth:

GENERAL PREPARATION (ESTER) The phenol (hydroxy aromatic nucleus) is reacted with the thiochloroformate in the presence of an HCl acceptor (such as pyridine), the alkali metal hydroxides such as sodium hydroxide, and the like, the latter as aqueous solu- Patented Aug. 29, 1967 The reactants, conditions of reaction and products are set forth below:

tions, at about room temperature unless otherwise indicated. Upon completion of the reaction the desired product is recovered by distillation under reduced pressure.

Exam- OH CHaQ-Jfia Exarn- HCI Acceptor (M.P.) or Percent -ple Hydroxyl Reactant or Base R Product Yield 1 .No. I 0.1mm.

l0. 0H CsH N Me (t) 87.4

O-l-SCH:

OH H

-O-CSOH= 11- 0H CaHsN Me I] 8693/0. 4 80 l O-CSCH3 12 0H CsHaN 7 Me I H 112115/0.3

0-O-SCH;

CHzO

CHaO

Based on thiochloroformate feed.

GENERAL PROCEDURE (REARRANGEMENT) The thio-carbonic-ester of the phenol obtained by reaction above outlined is mixed with an equimolar proportion of a Friedel-prafts catalyst (AlCl was used in the examples) and preferably with an inert solvent (orthodichlorobenzene has? been employed in the examples). The resulting slurry is heated at from about to 180 1 Yields reported are for purified materials.

C. until the evolution of HCl ceases. Any solid formed during the reaction is removed by filtration and the desired product recovered from the filtrate by extraction with an ether-hexane extractant. The extractant is removed by distillation to yield the desired hydroxyarylcarboxylic ester. The products obtained and the reaction conditions employed are set forth in the following table:

Example Reactant Temp., C. I Method of Product B.P., 0. Percent N o. Purification (M.P.) Yield 1 13 H 140-160 Steam Distilled.--" 0H 0 -100 26 o-o-soH, (2 mm.)

; i C-SCHa i z i if i Recrystallizjed i 0H -122) 10 Isooetanei 4 1 I, I I c1r3s-o=o v 14 .1- 0 120 Recrystalllzed OFH (77-79) 50 j g 2 Methanol; O -S C H: g j SCHa C1 5 J 1 y 1 15 l 120-130 Distilled -130 50 [I O (3 mm.) 0CS,CH; H R l C-SCH:

* Based on thiochloroiormate feed. 1 Yields repor fed are for purified materials.

9 Example 24 To illustrate the usefulness of the compounds having the generic Formula I as herbicide tests were carried out to determine the effectiveness of the named compounds as inhibitors to control the m-arigold.

The test compound was dispersed in water to prepare an aqueous composition containing 100 parts by weight of the compound per million parts by weight of ultimate mixture. This composition was employed for the treatment of seed germination beds which had been prepared and planted with the seeds of marigold. In the treating operations, the composition Was applied to the seed beds as a d-rench and at a dosage of about 0.23 acre inch of aqueous composition per acre. Other seed beds similarly prepared and planted were left untreated to serve as checks.

After about eleven days, the seed beds were examined to ascertain what control of the growth and germination of seeds had been obtained. The results are set forth in the following table.

In other tests some of the compounds were found effec- 35 tive in the control of the Marine Borer Limnoria, others as aquatic herbicides and the like.

We claim:

1. A compound having the formula wherein R represents a member selected from the group consisting of saturated aliphatic hydrocarbon radicals having from 1 to 18 carbon atoms, Ar represents an aromatic 4 nucleus selected from the group consisting of phenyl, and methoxy substituted phenyl derivatives, and n represents the integer of 2 when Ar is phenyl and 1 when A1 is methoXy phenyl.

2. A compound having the formula II o-o-sR having from 1 to 18 carbon atoms.

0 o-t'i-som fl) O-CSOHa n O-(J-SOHa References Cited UNITED STATES PATENTS 3,172,900 3/ 1965 Berezin et a1 260455 FOREIGN PATENTS 789,985 1/1958 Great Britain.

OTHER REFERENCES Al-Kazimi et al.: Vol. 77, J.A.C.S., pp. 2479-2482 40 (May 1955) Baker et al.: Vol. 82, J.A.C.S., pp. 1923-1928 (April 1960).

Powers et -al.: Vol. 78, J.A.C.S., pages 70-71 (January 1956).

CHARLES B. PARKER, Primary Examiner JOSEPH P BRUST, Examiner.

DELBERT R. PHILLIPS, Assistant Examiner. 

1. A COMPOUND HAVING THE FORMULA 